Device for driving a rotary element capable of deformation and of displacement parallel to its theoretical axis of rotation

ABSTRACT

A device for driving a rotary element, more particularly a rotary kiln, capable of deformation and displacement along its axis and comprising a toothed rim driven by a pinion mounted in a housing articulated on a fulcrum and bearing on two cylindrical tracks coaxial with the rim by way of at least one pair of rollers, characterized in that the housing is connected to a fixed block by a member capable of producing displacement of the fulcrum in a direction parallel to the axis of rotation of the kiln, freely following displacements of the kiln.

United States Patent Pei-e 1451 Dec. 19, 1972 541 DEVICE FOR DRIVING AROTARY 3,299,729 l/l967 Durand ..74/41o x EL M NT CAPABLE O 3.4903061/1970 Hansgen et al. ..74/41o 3,534,624 10/1970 Durinck ..74/410DEFORMATION AND OF 3,572,150 3/1971 Durand ..74/410 DISPLACEMENTPARALLEL TO ITS THEORETICAL AXIS 0F ROTATION Inventor: Gerard Pere, LeBreuil, France Assignee: Creusot-Loire, Paris, France Filed: Sept. 28,1971 Appl. No.: 184,557

Foreign Application Priority Data Field of Search ..74/4 1 0 ReferencesCited UNITED STATES PATENTS v 2/1965 Durand ..74/4l0 X PrimaryExaminer-Leonard H Gerin Attorney-William B. Kerkam, Jr.

[57] ABSTRACT A device for driving a rotary element, more particularly arotary kiln, capable of deformation and displacement along its axis andcomprising atoothed rim driven by a pinion mounted in a housingarticulated on a fulcrum and bearing on two cylindrical tracks coaxialwith the rim by way of at least one pair of rollers, characterized inthat the housing is connected to a fixed block by a member capable ofproducing displacement of the fulcrum in a direction parallel to theaxis of rotation of the kiln, freely following displacements of thekiln.

7 Claims, 9 Drawing Figures PATENT'ED DEC 19 I972 SHEET 2 OF 3 DEVICEFOR DRIVING A ROTARY ELEMENT CAPABLE OF DEFORMATION AND OF DISPLACEMENTPARALLEL TO ITS THEORETICAL AXIS F ROTATION The invention relates to adevice for driving a rotary element capable of deformation and ofdisplacement parallel to its theoretical axis of rotation.

Numerous driving devices are known for rotary elements liable todeformation, such as rotary kilns, grinders or steel converters. Anumber of proposed devices are intended to drive these rotary elementssatisfactorily in spite of the deformation which they undergo due toexpansion or due to changes in the stresses applied to them while theyare in use. The driving devices usually comprise a toothed rim fixed toand coaxial with the rotary element and means for rotating the rim byway of a driving member. The driving member must be able to follow thedeformations of the rim. The invention relates more specifically todriving devices in which the rim driving member comprises a housingprovidedwith at least two rollers each of which bears on one of twocylindrical tracks coaxial with the rim the rim, and at least one piniondriven by the rim rotat- Y ing means, mounted on the housing, having itsaxis parallel to that of the rim and meshing with the rim. The rimdriving pinion is therefore connected to the rim and can remain incontact with the teeth whatever the deformation to which the rim issubjected. Since the pinion must, of course, be held if it is totransmit rotary motion to the rim, the device comprises a member forconnecting the housing to a fixed component, this connecting memberbeing pivoted on a fulcrum for the housing. Contact between the pinionand the rim can be ensured either by the weight of the driving memberitself, if the latter is placed above the axis of the rim, or by aresilient member which is pivoted on the housing and which urges thepinion onto the rim by bearing on afixed component.

In order to leave the driving member as a whole some freedom ofmovement, so that it can follow the deformation of the rim whileremaining engaged, the connecting member is usually a draw-bar whoseends are connected by universal joints to the housing fulcrum and to afixed component. This form of coupling is generally fairly satisfactory.Apart from the deformation of the rim, however, it may happen that therotary element is displaced along its axis. This occurs, for example,with rotary kilns in which expansion may cause appreciable axialdisplacement of the rim due to the considerable length of the kiln, andto which, moreover, a reciprocating movement along their axis is usuallysystematically imparted to prevent the supportv ing rollers from alwaysbearing on the same parts of the running surfaces.

When the housing of the driving member is retained by a draw-bar pivotedat both ends, this bar turns on its pivot on the fixed component,following the longitudinal displacement of the rim, and the housingfulcrum therefore describes a circular are centered onthe fixed pivot.The bearing reaction, which is directed along the straight line joiningthe points at which the draw-bar is pivoted on the fixed component andon the housing, does not, therefore, remain perpendicular to thetoothing. As a result the load on the toothing is distributedasymmetrically, which restricts the performance of the toothing and alsocreates appreciable axial thrust which must be absorbed by an abutmenton the rim.

An object of the invention is to provide a driving device whichovercomes these disadvantages.

According to the invention, the connecting member is capable of causingdisplacement of the housing fulcrum in a direction parallel to thetheoretical axis of rotation of the rotary element, freely followingaxial displacement of the rotary element.

According to the supplementary feature of the invention, the bearingreaction remains substantially in the central plane of the pinion duringdisplacement of the rotary element.

A first embodiment of the invention, which will be described below, ischaracterized in that the'connectingmember is an articulated systemformed of a lever which is pivoted about the housing fulcrum and onwhose ends are pivoted two' rods of equal lengthsextending on each sideof the lever in a plane parallel to the pinion axis, the other end ofeach rod pivoting about a fixed axis perpendicular to this plane.

A second embodiment of the invention described below is characterized inthat the connecting member is at least one strut pivoted on the housingfulcrum and bearing-on a fixed plane perpendicular to the resultant ofthe stresses applied to the housing during rotation of the driven rotaryelement at its normal running speed, along a cylindrical surface whoseaxis passes through the fulcrum, is in the central plane of the pinionand is parallel to the said fixed plane.

The invention will now be described in detail with reference toparticular embodiments, given by way of example and illustrated in theaccompanying drawings, in which:

. FIG. 1 represents a cross-section through part of the driving rim fora rotary element and the drivin member;

FIG. 2 is an elevation in the direction II-II in FIG. 1, showing thedriving member illustrated in FIG. 1;

FIG. 3 is an elevation 'of the connecting member on a larger scale, asseen in the direction IIIIII in FIG. 1;

FIG. 4 is a section on a line IV-IV in FIG. 3;

FIG. 5 is a section on a line V-V in FIG. 3;

FIG. 6 is a diagrammatic perspective view of the connecting member;

FIG. 7 is a cross-section through a second embodiment of the invention;

FIG. 8 is an elevation of the connecting member in the second embodimenton a larger scale; and

FIG. 9 is a section on a line IX-IX in FIG. 8.

In the embodiment shown in FIGS. 1 to 6, the rotary element 1 is acylindrical drum surrounded by a rim 2, provided on its circumferencewith toothing 3 meshing with a pinion 4 whose axis is parallel to theaxis of the rim and which is mounted on a housing 5. This housingconsists chiefly of two side plates 51, 52 enclosing the pinion andconnected by spacers so that the housing is rigid enough to hold thepinion pivot.

The rim 2 is provided, on each side of its plane 0 symmetry, with twocylindrical tracks 21, 22 coaxial with the rim. A roller 53 pivotablymounted on the housing 5 runs along each of these tracks. The housing 5is articulated at a fulcrum 54, normally placed in the central plane ofthe pinion, on a system of articulated rods 6 (FIG. 2) consisting of alever 60 which is pivoted at its center on a ball centered on thefulcrum 54 and on whose ends two rods 61, 62 are pivoted, the other endsof these rods 61, 62 turning respectively on pivots 63, 64 mounted on afixed base 65. The lengths of the rods 61, 62 are equal. The pivots 63,64 are parallel to one another and perpendicular to a plane passingthrough the axis of the pinion 4. The articulated system 6 thereforeremains within this plane when it is deformed.

The articulated system 6 is shown diagrammatically in FIG. 6. It is wellknown that if in a mechanical system of this kind, known as a Wattsystem, the ratio between the lengths of the central lever 60 and of therods 61, 62 is suitably chosen, the mid-point 54 of the lever will bedisplaced along a substantially straight line when the system isdeformed, and the rods 61, 62 will turn through a substantially equalangle. As a result, a force exerted on the mid-point 54 at right-anglesto the direction of the straight line A along which this point shiftswill produce only a very small reaction in the direction of A due to thedifference of inclination between the rods 61 and 62, this differencebeing practically zero, of course, if certain limits are observed.

In the case of a rotary element such as arotary kiln, the amplitude ofthe admissible longitudinal displacements is known. It is easy tocalculate the lengths of the rods and of the central lever and toarrange the system so that the bearing reaction exerted by the housingon its fulcrum 54 is perpendicular to the direction A along which themid-point 54 may shift.

In general the pinion 4 is applied to the teeth 3 by a resilient member7 (FIG. 1) compressed between a fixed bearing block 71 and a pivot 72 onthe housing 5. From the force applying the housing to the rim, theposition of the rollers 53 and the orientation of the teeth reaction fora normal rotary-element driving torque, the average orientation of theresultant of the teeth in spite of axial displacement of the rotaryelement. It is therefore possible to transmit high torques'to the pinionat low speeds by way of a fixed motor-driven reducing unit 9.

Even higher torques can be transmitted to the rim by using, as describedin French Pat. specification No. 1,465,384, two intermediate pinionsmeshing with the rim, loosely rotatable on the housing 5 at somedistance from one another, and driven by a pinion which is axiallyconnected to the housing, is between the two intermediate pinions and isheld radially by its teeth. It is the latter pinion which will be drivenby the coupling shown in FIG. 2. Obviously, the stresses applied to theentire device will be taken into account when calculating the positionof the fulcrum 54 and the orientation of the plane of the articulatedsystem 6. i

The housing 5, which bears on the tracks 21 and 22.

. by way of rollers 53 and is connected to the lever 60 by forcesapplied to the housing can easily be deduced.

The plane of the articulated system 6 is therefore directed according tothis resultant.

When the rotary element is displaced along its theoretical axis ofrotation within the admissible limits, therefore, the bearing reactionis displaced parallel to itself and remains perpendicular to the axis ofdisplacement. As a result there is no appreciable axial component andtherefore no housing tilting couple. The pressure continues to bedistributed evenly along the toothing, and the gearing operates underexcellent conditions.

Advantageously, as shown in FIG. 2, the housing connecting member 6 justdescribedmay be combined with a coupling comprising a plurality ofarticulated systems similar to that forming the connecting member. Acoupling of this type is described in our US. Pat. application No.7,100,193 filed on 6.1.71. It enables a driving torque to be transmittedto the pinion 4 while adsorbing longitudinal displacement of the pinionrelative to the driving shaft, without causing any appreciable reactionto be exerted on the pinion. Clearly, the combination of the two devicesand the addition of a counterweight 8 to balance the stresses due to theweight of the coupling and of the transmission shaft ensure an excellentdistribution of the pressure over the a ball joint, canstill, of course,shift slightly in any direction and so follow any deformation of thetoothed rim or of the rotary element, as, in the assemblies proposedbefore.

In the embodiment shown in FIG. 7, the housing connecting member is astrut l0 articulated on a pivot 11 mounted on a fork joint 55 fixed tothe housing. The pivot 11 is preferably provided with a ball joint whosecenter forms the housing fulcrum 54, and is normally placed in thecentral plane of the pinion. I

The strut 10 is shown in detail in FIGS. 8 and 9.

This strut 10 is supported on a fixed plane 12 perpendicular to theresultant of the stresses applied to the housing during rotation of therotary element when driven at its normal running speed, by way of acylindrical surface 13 whose axis passes through the fulcrum 54 and isparallel to the plane 12 and to the central plane of the pinion, thefulcrum 54 being in the said central plane. This arrangement appliesif.the housing 5 has four rollers 53 arranged in pairs on each side ofthe pinion axis. Under these conditions the resilient bearing means 7can be sited so that the strut need support only the teeth reaction andis therefore placed parallel to the teeth reaction produced in the caseof a normal rotary-element driving torque.

The end of the strut is held in a fork joint 14 attached to the fixedsupport. The two side plates of this fork joint contain oblong orifices141 to receive a pivot 101 which passes through the strut. This pivotenables the strut to withstand unexpected traction, but does not impederotation of the strut on the bearing surface 13. Lastly, keys 15 whichslide in recesses in the strut and in the bearing member 12 prevent thestrut from sliding and oblige the strut to pivot on its bearing surface13.

With an arrangement of this kind, of course, the bearing reactionperpendicular to the plane 12 is displaced parallel to this direction inthe event of axial displacement of the rotary element, since the strutpivoting on its cylindrical bearing surface follows the displacement ofthe rotary element freely without producing a reaction against thehousing 5.

In this case, also, the provision of the fulcrum on a ball joint enablesthe housing 5 bearing on the rollers 53 to follow any deformation of therim while keeping the pinion engaged.

In the embodiment illustrated, the housing 5 was provided with fourbearing rollers and one articulated strut. Alternatively, of course, asin the embodiment shown in FIG. 1, only two bearing rollers might beused. In this case two struts would be provided, in order to absorb theresultant of the stresses applied to the housing.

The sole purpose of the resilient member 7 is to apply the pinion to therim, and its length can vary as it follows the displacements of therotary element. If it is pivoted on the bearing block 71, therefore, itcan transmit only slight axial reactions. However, to eliminate eventhese reactions, the bearing plane 71 is preferably parallel to thetheoretical axis of rotation of the rotary element, and the resilientmember 7 preferably bears on this plane either by way of an articulatedsystem similar to the system 6 shown in FIG. 1 or, like the strut 10,along a cylindrical surface whose axis is parallel to this plane andperpendicular to the axis of rotation of the rotary element. The supportwould be identical to that shown in FIGS. 8 and 9, and the resilientmember would therefore follow displacements of the rotary elementfreely, transmitting to the pinion a pressure which is always atright-angles to the pinion axis.

it has been stated that the plane of the articulated system 6 or of thestrut 10 is parallel to the resultant of the stresses applied to thehousing and also passes through the pinion axis. It may be useful tofurther separate the fulcrum from the tangent plane common to the pitchcircles of the sets of teeth, so that the plane of the strut forms withthe tangent plane an angle greater than the pressure angle. If so, thestress applying the pinion will increase in proportion to the torquetransmitted, removing any risk of separation. If the position of thehousing fulcrum is chosen correctly, the resilient member will thereforeneed to absorb, in addition to the weight of the driving member itself,only the force required to apply the pinion to the rim when stationary.

Obviously, the invention is not restricted to the details of the twoembodiments described. Other connecting members, such as slides, mightbe suitable, provided that they produce displacement of the housingfulcrum in a direction parallel to the theoretical axis of rotation,while freely following displacement of the r0- tary element so that thebearing reaction remains substantially in the central plane of thepinion, without the connecting member being able to transmit to thehousing an axial component due to the displacement of the rotaryelement.

In particular, the two embodiments described make it possible to absorbaxial displacement of the kiln of the order of 60 mm on each side of itscentral position.

A device of this kind can transmit high torques to the rim and cabtherefore use a fixed reducing unit, particularly if the device justdescribed is combined with a coupling of the type described in theabove-mentioned prior Application. Clearly, however, the same resultwould be obtained by combining the device described in the presentApplication with any other coupling capable of transmitting the torqueand of absorbing axial displacement without producing a reaction on thefloating pinion.

Lastly, it should be noted that the articulated system 6 used in theembodiment shown in FIG. 1 can absorb both thrust and traction withoutany axial reaction. If

desired, the housing fulcrum could therefore be placed to either side ofthe axis of the driving pinion.

I claim:

which bears on one of two cylindrical tracks coaxial with the rim andsituated on each side of the plane of symmetry of the rim, at least onepinion driven by the rim rotating means, mounted on a housing and havingits axis parallel to that of the rim and meshing with the rim, and amember for connecting the housing to a fixed component, this connectingmember being pivoted on a fulcrum for the housing, characterized in thatthe connecting member is capable of causing displacement of the housingfulcrum in a direction parallel to the theoretical axis of rotation ofthe rotary element, freely following axial displacement of the rotaryelement.

2. A driving device as claimed in claim-1, characterized in that thebearing reaction remains substantially in the central plane of thepinionduring displacement of the rotary element.

3. A driving device as claimed in claim 1, characterized in that theconnecting member is an articulated system formed of a lever which ispivoted about the housing fulcrum and on whose ends are pivoted two rodsof equal lengths extending on each side of the lever in a plane parallelto the pinion axis, the other end of each rod pivoting about a fixedaxis perpendicular to this plane.

4. A driving device as claimed in claim 1, characterized in that theplane of the articulated connecting system for the housing is directedaccording tothe resultant of the stresses applied to the housing duringrotation of the driven rotary element at its normal running speed.

5. A driving device as claimed in claim 1, characterized in that theconnecting member is at least one strut pivoted on the housing fulcrumand bearing on a fixed plane perpendicular to the resultant of thestresses applied to the housing during rotation of the driven rotaryelement at its normal running speed, along part of a cylindrical surfacewhose axis passes through the fulcrum, is in the central plane of thepinion and is parallel to the said fixed plane.

6. A driving device as claimed in claim 1, characterized in that the rimrotating means comprises a combined, fixed driving and reducing unitdriving the pinion by way of an extension provided with a couplingcapable of absorbing axial displacement of the pinion relative to thereducing unit without transmitting an axial reaction to the pinion, thehousing being provided with means for balancing the weight of theextension and of the coupling.

7. A driving device as claimed in claim 1, characterized in that theconnecting member extends in a plane passing through the pinion axis andforming an angle greater than the pressure angle with the tangent planecommon to the pitch circles of the sets of teeth.

1. A device for driving a rotary element capable of deformation and ofdisplacement parallel to its theoretical axis of rotation, comprising atoothed rim fixed to and coaxial with the rotary element and means forrotating the rim by way of a driving member comprising a hub providedwith at least two rollers, each of which bears on one of two cylindricaltracks coaxial with the rim and situated on each side of the plane ofsymmetry of the rim, at least one pinion driven by the rim rotatingmeans, mounted on a housing and having its axis parallel to that of therim and meshing with the rim, and a member for connecting the housing toa fixed component, this connecting member being pivoted on a fulcrum forthe housing, characterized in that the connecting member is capable ofcausing displacement of the housing fulcrum in a direction parallel tothe theoretical axis of rotation of the rotary element, freely followingaxial displacement of the rotary element.
 2. A driving device as claimedin claim 1, characterized in that the bearing reaction remainssubstantially in the central plane of the pinion during displacement ofthe rotary element.
 3. A driving device as claimed in claim 1,characterized in that the connecting member is an articulated systemformed of a lever which is pivoted about the housing fulcrum and onwhose ends are pivoted two rods of equal lengths extending on each sideof the lever in a plane parallel to the pinion axis, the other end ofeach rod pivoting about a fixed axis perpendicular to this plane.
 4. Adriving device as claimed in claim 1, characterized in that the plane ofthe articulated connecting system for the housing is directed accordingto the resultant of the stresses applied to the housing during rotationof the driven rotary element at its normal running speed.
 5. A drivingdevice as claimed in claim 1, characterized in that the connectingmember is at least one strut pivoted on the housing fulcrum and bearingon a fixed plane perpendicular to the resultant of the stresses appliedto the housIng during rotation of the driven rotary element at itsnormal running speed, along part of a cylindrical surface whose axispasses through the fulcrum, is in the central plane of the pinion and isparallel to the said fixed plane.
 6. A driving device as claimed inclaim 1, characterized in that the rim rotating means comprises acombined, fixed driving and reducing unit driving the pinion by way ofan extension provided with a coupling capable of absorbing axialdisplacement of the pinion relative to the reducing unit withouttransmitting an axial reaction to the pinion, the housing being providedwith means for balancing the weight of the extension and of thecoupling.
 7. A driving device as claimed in claim 1, characterized inthat the connecting member extends in a plane passing through the pinionaxis and forming an angle greater than the pressure angle with thetangent plane common to the pitch circles of the sets of teeth.